Chronic inflammation induced by amyloid-beta (Aβ) plays a key role in the development of age-related macular degeneration (AMD), and matrix metalloproteinase-9 (MMP-9), interleukin (IL)-6, and IL-8 may be associated with chronic inflammation in AMD. Sirtuin 1 (SIRT1) regulates inflammation via inhibition of nuclear factor-kappa B (NF-κB) signaling, and resveratrol has been reported to prevent Aβ-induced retinal degeneration; therefore, we investigated whether this action was mediated via activation of SIRT1 signaling. Human adult retinal pigment epithelial (RPE) cells were exposed to Aβ, and overactivation and knockdown of SIRT1 were performed to investigate whether SIRT1 is required for abrogating Aβ-induced inflammation. We found that Aβ-induced RPE barrier disruption and expression of IL-6, IL-8, and MMP-9 were abrogated by the SIRT1 activator SRT1720, whereas alterations induced by Aβ in SIRT1-silenced RPE cells were not attenuated by SRT1720. In addition, SRT1720 inhibited Aβ-mediated NF-κB activation and decrease of the NF-κB inhibitor, IκBα. Our findings suggest a protective role for SIRT1 signaling in Aβ-dependent retinal degeneration and inflammation in AMD.

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BackgroundThis study aimed to evaluate whether obliquely angled and ring-shaped titanium mesh cage (TMC) end structures can improve the compressive load on the endplate interface in anterior cervical corpectomy and fusion (ACCF).Material/MethodsA total of 23 volunteers underwent cervical lateral x-ray. The oblique angle of the superior endplate was measured, which was used to construct the gradient of the TMC end. Forty-two fresh cadaveric vertebral bodies were harvested and randomly distributed among four TMC groups with different ends. The baseline indicators of bone mineral density and anteroposterior and transverse dimensions were recorded. The superior endplate was placed at an angle of 12° when performing uniaxial compression testing. The maximum loads of the four TMCs were assessed.ResultsThere were no significant differences among the groups regarding the baseline indicators. The conventional TMC had the lowest maximum load (1362.3±221.78 N, p<0.05), whereas the TMC with an obliquely end ring had the highest maximum load (2095.82±285.64 N, p<0.05). The maximum loads of the TMCs with oblique footprints and flat end ring were much higher than that of the conventional TMC (p<0.05) but significantly lower than that of the TMC with the obliquely end ring (p<0.05), with average values of 1806.91±246.98 N and 1725.3±213.33 N, respectively.ConclusionsBoth the ring shape and oblique angle of the TMC end contributed to an increase in compressive force and are advocated for use in TMC structure optimization to decrease the incidence of TMC subsidence in ACCF.

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The paper presents a finite-element analysis of a metro tunnel project using the URUP method in which the shield machine is launched and received at the ground surface level. During the tunnelling process, the cover depth varied from 0.7D (D is the excavation diameter) to-0.3D in which case the shield machine was partially above the ground surface. A three-dimensional finite element model is proposed via the commercial software ABAQUS considering the actual geological condition and tunnelling procedures. Elasto-plasticity constitutive models are utilised for the top three strata in the finite element analysis (FEA). Constant gradients corresponding to material density are assumed for the face supporting pressure and the grouting pressure in the model. The ground contraction method is employed to simulate the shield-induced volume loss. The numerical model is firstly validated against the field measurement data considering the surface settlement. Parametric studies are performed subsequently to investigate the influence of some key tunnelling variables including cover-to-diameter ratio and face supporting pressure on the ground responses. According to the FEA, a critical cover depth of 0.55D is proposed for URUP method